Examination of interface roughening in ion irradiated Cu/Nb films by computer simulation and by x-ray diffraction

Interfacial roughening during ion irradiation of an immiscible system is investigated by Monte Carlo computer simulation and by an x-ray diffraction technique called crystal truncation rod (CTR) analysis. In the simulations, ion flux and sample temperature are varied, and the system is allowed to evolve under irradiation until it reaches a steady state behavior. The observed behaviors are then sought experimentally in the Cu/Nb system implanted with 2 MeV Kr+ ions at different sample temperatures. Analysis of the roughness at the Cu interface is based upon the existence of a crystal truncation rod, which contains information on exactly how the crystal is terminated, or, in other words, the interfacial roughness. Rutherford backscattering spectrometry (RBS) is also used to study the intermixing of the Cu and Nb layers